Carbonaceous molding material for foundry operations



April 15, 1958 e. R. MEYERS ETAL 2,830,913

CARBONACEOUS MOLDING MATERIAL FOR FOUNDRY OPERATIONS Filed Oct. 11, 19554 Sheets-Sheet 1 Fig.l

G. Roland Meyers Everett G. Gentry Inventors Small, Dunham 8 Thomas By iAttorney April 15, 1958 G. R. MEYERS ET AL 2,830,913

CARBONACEOUS MOLD-INC MATERIAL FOR FOUNDRY OPERATIONS Filed Oct. 11,1955 4 Sheets-Sheet 2 Fig. 2

6. Roland Meyers Everett 6. Gentry Inventors Small, Dunhom 8: Thomas Byjut/{W Attorney April 1 1958 G. R. MEYERS ETAL 2,830,913

CARBONACEOUS MOLDING MATERIAL FOR FOUNDRY OPERATIONS- Filed 001;. 11,1955 4 Sheets-Sheet 3 IOR G. Roland Meyers Ever tt 5 Gentry Inventors Aril 15, 1958 e. R. MEYERS ET AL CARBONACEOUS MOLDING MATERIAL FORFOUNDRY OPERATIONS Filed Oct. 11, 1955 4 Sheets-Sheet 4 G. RolandEverett G.

Small, Dunhum 8| Thomas By W Attorney United States Patent CARBONACEOUSMGLDING MATERIAL FOR FOUNDRY OPERATIONS Gustave Roland Meyers, AnnArbor, and Everett G.

Gentry, Lincoln Park, Micl1., assignors to Esso Research and EngineeringCompany, a carpuration of Delaware Application October 11, 1955, SerialNo. 539,778

8 Claims. (Cl. 106-383) The present invention relates .to an improvedcarbonaceous material for molding metals. It more particularly pertainsto an improved metals casting composition comprising fluid coke and acompounding material, for the formation of molds and cores used to castarticles of metal, including ferrous and non-ferrous metals and alloysthereof.

It has been discovered that fluid coke having less than 7 Wt. percentsulfur serves as a superior metals casting material, and can be used toreplace sand in molds and cores either partially or, more preferably,entirely. More specifically, this invention proposes that fluid cokeoflow sulfur content, by itself or in an admixture with sand, serves asan excellent material to form green, dried and baked molds, green andbaked cores, mold facings, shell molds and cores, and the like. Fluidcoke is an ideal metals casting material because it is carbonaceous,available in large quantities, and has a natural particle size similarto sand.

Superior results are obtained by using fluid coke as a metals castingmaterial in that the articles cast have truer dimensional accuracy,smoother surface finish and require lesser cooling times. Because thethermal expansion of fluid coke is considerably less than that ofconventional foundry sands, castings may be mdae with risers that aresubstantially reduced in size. In some cases the risers may beeliminated. Thus, more castings may be obtained from a melt and theamount of metal that must be recycled to the cupola for remelting issubstantially reduced. Another advantage of fluid coke is that it is notwetted by molten iron because it is carbonaceous. This produces asmoother metal surface, and tends to prevent metal penetration andveining.

The hydrocarbon oil fluid coking process has recently been introducedinto petroleum refinery operations. In this fluid coking process, anoil, usually a low value heavy residual oil, is converted by pyrolysisto relatively lighter hydrocarbons and coke by contact with finelydivided heat carrying solid particles maintained at a temperature in therange of 850 to 1500 F. or above. The heat carrying solids arepreferably maintained as a fluid bed in a coking zone, but the processcan be carried out in a tranfer line. The coke produced by the pyrolysisdeposits on the fluidized solids, layer by layer, and becomes a partthereof. Although some of the coke produced by the cracking may beconsumed by burning to supply heat in the coking process, a substantialamount is removed as by-product. The heat carrying solids normally usedare coke particles produced by the process such that the byproduct cokeis of uniform composition. The by-product fluid coke produced has a highpercentage of carbon with an ash and sulfur content characteristic ofthe oil feed stock.

' The particle size of the heat carrying solid used in the V cokingprocess is in the range of about 18 to 400 U. S.

sieve number, with the median particle size normally being in the rangeof 45 to 70. The by-product coke is of about the same size. This uniqueby-product coke is characterized by its spherical or ovoid shape,laminar structure, high density and hardness, and differs substantiallyfrom the cokes produced by the pyrolysis of hydrocarbonaeeous solids andoils by other processes. The term fluid coke is intended to include thesolid product of the fluid coking process, i. e., the by-product coke orraw fluid coke, gefides the treated forms of the raw fluid coke,described e ow.

It has now been discovered that fluid coke as produced, but preferablyraw fluid coke that has been pretreated, serves as an excellent metalscasting material to form molds, cores, and mold and core washes. Fluidcoke is a unique carbonaceous metals casting material because it is morenearly equivalent to sand in particle shape, hardness and density thanany other carbonaceous material heretofore commercially available.

The preferred pretreatment of fluid coke comprises calcination and/ordesulfurization to decrease its volatile matter and sulfur content, andto increase its density. The product so obtained by this pretreatment ishereinafter referred to as calcined fluid coke. Although desulfurizationtreatment of raw fluid coke normally results in calcination of the coke,it is not necessarily always true and the term calcined fluid cokehereinused, includes fluid coke that has only been desulfurized.

Calcination of the raw fluid coke to primarily increase its density anddecrease its volatile matter content may be carried out by anyconventional method. Generally, calcination of fluid coke simplyinvolves heat soaking at relatively high temperatures, e. g., 1800 F. orabove, for a suitable period of time. This is preferably done separatefrom the coking process, but may be carried out Within the process, asby segmenting the burner used to heat fluid coke so as to form a specialhigh temperature zone from which the by-product coke can be withdrawn.The calcination or heat soaking may be carried out while the fluid cokeis in the form of a fixed, gravitating or fluid bed. A preferred methodof calcination is to quickly heat the raw fluid coke up to about 2400 to2800 F. by direct contact with high temperature flue gases or productsof combustion, and then quickly separating the heated coke from thegases. The coke so heated is then maintained as a gravitating bed in arefractory lined soaking chamber for about one hour to complete thecalcination. In this preferred manner of operating, volatile sulfurcompounds, relatively undiluted with flue gases, can be recovered fromthe soaking zone.

It will be apparent to those skilled in the art that raw fluid coke canbe calcined by repeated use in the casting process, and the termcalcination is intended to include this. Thus, a small amount, say 5%,raw fluid coke can continuously be added to the reservoir of materialused to form molds and/ or cores in a foundry, and by repeated usebecome suitably calcined.

Desulfurization of raw fluid coke or of fluid coke that has beencalcined can be accomplished in several ways. One preferred method is tooxidize the coke by fluidizing it with an oxygen containing gas at atemperature in the range of 600 to l500 F. for a time suflicient toconsume over 3 Wt. percent of the fluid coke. An especially preferredmethod of desulfurization comprises this ozidation treatment followed byhydrogenation With a free hydrogen containing gas at temperatures above1100 F. In some cases the fluid coke may be desulfurized withoutpreliminary heat soaking, by contact with a desulfurizing gas such ashydrogen, ammonia, sulfur dioxide, etc. When using hydrogen it ispreferred to maintain the temperature above 1100" B; when using sulfurdioxide, the temperature is preferably maintained above 1800 F. Also,pressures of about 35 to p. s. i. or above are useful duringdesulfurization.

Instead of treatment with a desulfurizing gas, the coke can bedesulfurized simply by a high temperature thermal treatment. Thus, attemperatures of about 2400-2800 F., the sulfur compounds in coke can bebroken down and driven off. At the lower temperature, several hours ofheat soaking may be required to remove the sulfur.

in some uses it may be preferred, besides calcining the coke, to furtherpretreat it as by treatment with a solvent or by impregnating it with asuitable material such as water glass or finely divided graphite todecrease its porosity.

Fluid coke as removed from the fluid coking process, when coking thecustomary residual oil feed stocks, normally will have a sulfur contentup to about 7 wt. percent or above. it is preferred to reduce the sulfurcontent if necessary, by the above treatments, to below about 7 wt.percent to prepare it for use in foundry operations because higheramounts of sulfur may produce intolerable amounts of noxious fumes. Rawfluid coke may, however, itself be used in casting operations ashereinafter described.

To illustrate the change in properties that occurs during differenttreatments of raw fluid coke, Table'l is presented. The examples givenfor each type of coke are based on raw fluid coke having an originalmedian particle size of about 235 microns, obtained by the fluid cokingof a Hawkins residuum having a gravity of 4.3 A. P. 1., a Conradsoncarbon of 26 wt. percent, an initial boiling point of 882 F. (atmos.pressure equivalent), and a point of 1010 F. The coking was at atemperature of about 1000 F.

The calcined fluid coke example is based on treating raw fluid coke as agravitating fluid bed in an elongated vertical calcining chamber, at atemperature of about 2100 F. for a time up to about hours.

The desulfurized fluid coke example was obtained by treating raw fluidcoke as a gravitating moving bed in an externally heated elongatedvertical silicon carbide brick-lined calcining tower. The coke washeated to a temperature up to about 2400 F. for a time of about 24-hours, in the presence of a small amount of nitrogen stripping gas.

TABLE I Examples Raw Oalcined Desul- Fluid Fluid furized Coke Coke FluidCoke Size, A. I S. No 52 68 75 True Density, grms Ice. 1. 48 1. 95 1. 86Bulk Density, lbs [gain 9. 6 9. 6 9.15 Moisture, wt. percent.-. 0. 5 niln11 Sulfur, \vt. percent- 6. 7 5. 9 2.0 Ash, wt. percent- 0. 6 0. 8 0.3Carbon, wt. percent. 88. 3 97. 7 Hydrogen, Wt. percent 1. 8 nil VolatileMatter, wt. percent 5. 6 0.2 ml Base Permeability 1 /45 25/45 25/45 1According to 6th ed., Foundry Sand Handbook.

Generally speaking, calcination of fluid coke normally having a sulfurcontent of l-12 wt. percent, will reduce its volatile matter contentbelow about 1 wt. percent and sulfur content by 520%, and increase itstrue density above 1.7 grms./cc. Desulfurization will reduce sulfurcontent to below 3 wt. percent. it is preferred to use fluid coke havingcharacteristics falling in these ranges, as superior results areobtained even over raw fluid coke.

Fluid coke, including raw, calcined, and calcineddesulfurized fluidcoke, is preferably used as the principal constituent in molds, cores,washes, mold facing materials, mold backing materials, etc., replacingsand entirely, but can, however, be used in lesser amounts admixed withsand, or in minor amounts (0.5 to 25%) used as an additive, the termmetals casting material" being intended to include all of these uses.Any type of mold and/ or core can be made according to this inventionincluding, for example, conventional green, air dried, baked, shell,sand spun, oil, cement and investment molds, and green, air dried,baked, shell, CO process, and cement cores. The molds and cores may beformed either by hand ramming or with mechanical equipment. When reducedin particle size, fluid coke can serve as an ingredient in mold and corewashes.

in the "ration of molds, cores, and washes, fluid coke is ad Led withconventional additives or compounding materials cnstomarily used in thepreparation and shaping of molds and cores. By compounding materials itis meant to include conventional binders such as water, oils, compoundedcore oils, marine oils, iron oxide, drying oils, silica and wood flour,bentonite, dextrine, sea coal, cereal, clay, sugars, lignin sulfite,thermosetting and thermoplastic resins, pitch, rosins, etc.; to includeconventional mold additives such as water, oils, resin, cereal,bentonite, clays, sea coal, iron oxide, water glass, silica and woodflours, water soluble binders, sand and clay; and to includeconventional mold and core wash, paste and filler ingredients, such aswater, graphite, plumbago, sea coal, resins, corn oil, molasses, clay,organic solvents, dextrine, bentonite, gelatin, zircon and silicaflours, etc. Molds and cores made of fluid coke can be used to castferrous and non-ferrous metals and their alloys including gray, nodularand malleable iron, aluminum, magnesium, copper, lead, etc., and copperbase and steel alloys.

Figure 1 through 4, showing various articles cast according to thisinvention, are presented to further clarify this discussion.

Calcined' fluid coke used as a metals casting material results in asuperior cast product. The castings possess truer surface dimensions andexterior and interior contours, and have a more perfect finish. Fewercasting defects result.

The relatively low thermal expansion of fluid coke, as compared toconventional molding and core sands, is a highly desirablecharacteristic. It results in fewer casting defects that areattributable to expansion-contraction forces developed in the moldand/or core by the heat of the metal'during and shortly after pouring.Fluid coke has been found to be at least equivalent, if not superior, tozircon sand in this respect. A fluid coke mold has to of the expansionof a conventional sand mold. The relatively small thermal expansion offluid coke and its more rapid heat transfer characteristics permit thecasting of a metal using a smaller riser, or fewer risers, whichsubstantially reduces the amount of metal that must be recycled. Fluidcoke produces a good reducing atmosphere when pouring a mold, even whenused as an additive.

The faster cooling obtained through the use of fluid coke permitsshorter mold cooling times to be realized. When casting non-ferrousmetals such as brass and aluminum, this higher rate of cooling resultsin castings having a finer grain size and structure than that normallyobtained, which is highly desirable. It will be apprcciated by thoseskilled in the art that the higher heat conductivity of fluid coke ascompared to sand, appreciably decreases baking times and/or temperaturesof baked molds and cores, and results in a more uniform baking.

Because fluid coke has a bulk density about 20% less than conventionalsand, a lesser weight of material can be used, thereby decreasinghandling costs. It has been found that when casting steels, there is acase hardening effect caused by the fluid coke which is desirable insome instances. With gray cast iron which is fully saturated withcarbon, the carbonaceous material does not affect the casting. Becausefluid coke is substantially pure carbon, molten iron does not tend towet or adhere to it.

This greatly reduces or eliminates metal penetration, veining, etc., andimproves surface finish. When con ventional sand is used, iron silicate,a w melting slag and forerunner to veining, may be formed. This cannothappen with fluid coke.

Tests have shown that fluid coke when used in molds, does not suffer anysubstantial loss and may be reused. It has, in fact, been found thatreused calcined fluid coke or shake-out fluid coke has some advantagesbecause the previous use causes some further calcination and desulfurization of the coke, thereby improving its properties.

Generally, it is desired that the sulfur content of fluid coke be below7 wt. percent because of the fumes created and/or to minimize the sulfurpick up on the surface of the casting. With ferrous metals, particularlygray cast iron, it is preferred to use fluid coke having a sulfurcontent below 3 wt. percent because a higher sulfur content may resultin an appreciable formation of iron sulfide on the surface of thecasting. This may cause undesirable cracking and hardening of thesurface. In some instances, however, this may be an advantage, e. g.,when the iron is compounded with manganese. The sulfur in the cokepreferentially forms manganese sulfide, which imparts improvedproperties to the casting. With nonferrous metals, the presence ofsulfur also may not necessarily be detrimental, particularly in castingbrass and aluminum. When casting magnesium, the raw fluid coke of highsulfur content may be preferred because sulfur is normally used as aninhibitor in mold and core mixtures in casting magnesium.

Generally speaking, it has been found that greater amounts of certainadditives must be used when compounding green molds of fluid coke, whilethe amount of other types of additives normally used can be reduced oreliminated over that normally used with sand. For example, up to 50%more water may be used with fluid coke. When using oils, such as drying,marine, and/or conventional core oils, the amount of oil used isnormally somewhat greater than that used with core sands because of thegreater volume per weight of fluid coke. With molds and cores, it ispreferred to fully temper the coke particles with water before adding aliquid binder.

The fluid coke is, of course, comminuted if necessary, either before orafter calcination, and classified to obtain the proper size and sizedistribution needed in the particular casting process.

Tests have been conducted to determine the range of uses to which fluidcoke may be applied. Gray cast iron, steel, bronze, (brass), andaluminum have been tested in commercial operation using raw, calcined,or calcineddesulfurized fluid coke to form green molds, shell molds andcores. The-mold-forming and casting process used in some cases wherethose then being used to make commercial articles of manufacture. Fluidcoke was used to replace in its entirety, and partially conventionalmolding sand. Tests were also conducted under more severe conditions ofcasting bronze, specifically bronze pump impellers, where zircon sand isused because of its low thermal expansion characteristics to obtain agood casting.

In all cases, calcined fluid coke was found to produce a casting equal,and more often superior, to the conventional cast product. Taking inaccount the different physical characteristics of fluid coke, themolding procedures used were substantially the same.

Example I Fluid coke was used to form a cope and drag for the casting ofa commercially manufactured pump head. The pump head of gray cast ironwas cast in molds made of raw fluid coke, of calcined-desulfurized fluidcoke, and

of conventional molding sand. The properties of the raw TABLE 11 RawGalcined Sand, Coke, Coke, Wt. U. S. Sieve N0. Wt. Wt. Percent PercentPercent Retained Retained Retained 0.4 1.0 0. 2 0. 2 2. 6 0. 4 2.0 3. 63.8 32. 2 12. 3 17.0 43.8 28. 7 34. 4 15. 6 23.0 30. 2 3. 4 15.1 8.8 1.4 8. 7 2. 4 0. 2 2. 2 0.8 0. 2 2. 0 0. 6 r 1 0. 5 A. F. S. Fineness 52 775 63 1 Clay.

TABLE III Raw Calclned Conven- Fluid Fluid tional Coke Coke Sand MixtureMixture Composition: 1

Raw Fluid Ookeuwezight percent Oalcined Fluid Coke do Sand doMogul-Cereal Binder do Wheat Flour do. Wood Flour .do Western Bentonitedo.

Southern Bentonite. do Sea Coal Water Physical Properties:

Green Permeability Green Compressive Strength p. s. i. Deformation,percent- Hot; Strength 1,500 F. Hot Strength 2,000" F., p. s ThermalExpansion 1,500" F.,

1n 0. 004 0.022 Mold Hardness, Cope 70 70 55 Mold Hardness, Dra 75 75 75Pour Temperature, F 2, 580 2, 580 2, 540

This and subsequent tables are based on coke (and sand where applicable)as totaling wt. percent, with all other ingredients being wt. percentbased on coke and/or sand.

2 This is shakeout coke.

3 In 3 min., then contracted to 0.024 inlin. in 12 min.

In subsequent tests it was noted that one-half hour after the pouring ofthe castings, when the molds were shaken out, the casting from theconventional mold was at cherry red heat while those from the fluidcoke, both raw and calcined, were at black heat. This shows that fluidhas a much higher heat conductivity which is desirable because itminimizes shrinkage of the casting.

Figure 1 shows the castings obtained from this test. The casting markedSR is from the conventional sand mold, the one marked 8 is from the moldusing raw fluid coke, and the one marked 9 is from the mold usingcalcined-desulfurized fluid coke. It is to be noted in the drawing thatthe riser, indicated by an arrow, attached to pump head #9 is notdepressed or pipe while riser of the conventional mold shows piping.This illustrates that metal was drawn into the mold during the coolingprocess in the conventional mold because of the thermal expansion of themold, and because of the slower cooling time. The riser from thecalcined fluid coke mold is more uniform and does not display thispiping. This illustrates that in some instances the riser may beeliminated and may, in most cases, be substantially reduced in size.

Under similar conditions, calcined fluid coke (not desulfurized), havinga sulfur content of 5.9 wt. percent and volatile matter content of 0.2wt. percent, was used to form a mold for a cast gray iron pump head.Molds were cast using a riser and without a riser, using for comparisonconventional sand molds. The castings were poured at 2620 F. Thecastings using only calcined fluid coke possessed a better surfacesmoothness than those from conventional sand molds, but not as smooth asthose from calcined-desulfurized fluid coke. The calcined fluid cokewithout a riser produced a satisfactory casting.

Malleable cast iron can be cast as well as gray cast Iron.

Steel was also cast in a pump head shaped mold. There was found'to be asurface case hardening effect which in some cases may be desirable.

Sulfur prints were taken to determine the extent of sulfur pick up bythe castings. In no case was it found to be detrimental as, for example,to interfere with subsequent machining, because the thickness of thesulfurcontaining layer in the casting was minor. Sulfur pick up usuallyresults in a negligible hardening of the surface.

Example 11 Fluid coke having a size distribution as in Table II wasfabricated into the mold for the casting of bronze having thespecification: Brass #165 -USN A. S. T. M. B30 alloy 2A-copper baseingots A. S. T. M.NILB 1654l-bronze castings. Concurrently with castingof bronze in a calcined fluid coke mold, an identical casting was madein a conventional sand mold. The composition and properties of the moldsare given in Table IV.

TABLE IV Calctned Fluid Sand Coke Mixture Mixture Composition:

Sand weight percent. 100 Oalcined Coke do 100 Southern Bentonite do 5.14. 8 Pitch do 1.0 1. Water 3.9 3. 4 Physical Properties:

Moisture, wt. percent- 3. 8 3.3 Green Permeability 37 52 GreenCompressive 4.7 8.2 Deformation, percent 0.021 0.012 Hot Strength 1,500F., p. s.i 180 180 Hot Strength 2,000 F., p. s. L. 6 102 Mold Hardness,Cope 45 75 Mold Hardness, Drag 55 75 Pour Temperature, F 2, 250 2, 250

The resulting casting from the calcined fluid coke mold shown in theleft side of Figure 2 had a smoother surface finish than the oneproduced in a conventional sand mold shown in the right side of Figure2. What is more important, the grain structure of the bronze castingproduced from the calcined fluid coke mold was considerably finer. Thisis a desired characteristics because it materially improves themachinability and strength of the castmg.

Example III Fluid coke was used to form shell molds for casting acommercially produced aluminum drill housing, as shown in Figure 3.Calcined-desulfurized fluid coke of a particle size given in Table IIwas mixed with 6.1% of a commercial phenol resin binder and used to formthe shell mold identified as number 10 in Figure 3, and 6.0% of the sameresin was mixed with sand for the shell mold marked 10R. The cores usedwere made of sand and not of fluid coke. The casting produced with fluidcoke molds had a better surface finish, metal grain structure, anddimensional design than castings produced by conventional shell moldingmethods. This example shows that superior results are obtained usingfluid coke as a metals casting material when casting aluminum.

8 Example IV Calcined-desulfurized fluid coke was used by itself ormixed with zircon sand to make cores for a commercially produced bronzepump impeller requiring a high degree of perfection. Table V lists thecompositions of the cores and of similar cores made from conventionalzircon said, and Table VI gives the properties of the cores. All cores,after baking in a rack oven at about 460 F. for 1 /2 hours, were coatedwith silica wash and dried for 30 minutes in a rack oven. The bronze waspoured at 2075 F. simultaneously into molds having zircon sand cores andmolds having fluid coke cores. The molds were conventional, bake,pitch-bonded molds.

TABLE V Conven- This Intional, ventlon,

Wt. Wt.

percent percent Zircon Sand Fluid coke through mesh..- 38 Fluid cokethrough 8 mesh. 62 Mogul-Cereal Binder 2. 0 Core 2.0 Water 2.0

TABLE VI Conven- This Intlonal vention Moisture, wt. percent 0.8 7.0 DryPermeability 39 39 Tensile Strength, Lab 368+ Scratch Hardness, Lab 98Tensile Strength, after 1% hrs. at 500 F 118 Scratch Hardness, after 1%hrs. at 500 F 100 Figure 4 illustrates vertical cross-sections of thecastings produced. The letter Z indicates a casting produced by usingconventional zircon sand cores, and the letter C indicates a castingusing fluid coke cores. As evidenced by Figure 4, the fluid coke corecasting shows smooth internal surface and freedom from metalpenetration. It was equal in all respects to casting Z and did notsuffer the shrinkage void of casting Z. This example shows that fluidcoke can be used to make cores at least equal, if not superior, tozircon sand cores.

Cores comprising 25/75, 50/50, and /25 fluid coke to sand were made upand found to be satisfactory when compared to conventional cores.

An A. F. S. baked tensile core specimen, 1 thick, comprising 2% cereal,2% oil, 4% water, 50% calcined fluid coke, and 50% core and sand wasbaked at 400 F. and peak strength was developed in less than 45 minutes.This illustrates the better heat conductivity of fluid coke because testcores of sand normally require a longer baking time.

The following Table VII presents preferred typical ranges ofcompositions that can be used to form green, baked oil-bonded and shellcores and molds, which are preferred applications of fluid coke.

TABLE VII COMPOSITION RANGES on MOLDS AND corms Weight percent of GreenBaked Shell gluid Coke...

It will be appreciated by those skilled in the art that because of thecarbonaceous nature of this new casting material, in many instancesconventional additives such assume as pitches, plumbago, graphite, andsea coal formerly compounded with molding sands may be dispensed with.

It can be seen that fluid coke results in a casting process that is morerapid and produces acasting of truer accuracy and superior surfacecharacteristics, because it minimizes mold movement. One advantageaccruing to fluid coke is that risers may be eliminated or substantiallyreduced in size, thus permitting foundries to approach 100% yieldthrough minimizing remelting of risers. Other principal advantages offluid coke are that it has a low thermal coeflicient of expansion, and ahigher heat conductivity when compared to sand, and is not wetted bymolten iron.

Having described this invention, what is sought to be protected byLetters Patent is succinctly set forth in the following claims.

What is claimed is:

l. A metal molding composition consisting essentially of fluid coke, anda compounding material, said fluid coke having been produced bycontacting a heavy petroleum oil coking charge stock at a cokingtemperature with a body of fluidized coke particles in a reaction zonewherein the oil is converted to product vapors and carbonaceous solidsare continuously deposited on the coke particles, removing productvapors from the coking zone, heating a portion of the coke from thecoking Zone in a heating zone to increase the temperature of saidfluidized particles, returning a portion of the heated coke particlesfrom the heating zone to the coking zone and withdrawing coke productparticles.

2. The composition of claim 1, wherein said fluid coke has a sulfurcontent below 7 wt. percent, a volatile matter content below 1 wt.percent, and a true density above 1.7 gins/cc.

3. An improved metals casting form which consisting 10 essentially of anadmixture of calcined fluid coke and a compounding material formed tothe desired shape.

4. The form of claim 3 wherein said admixture consisting essentially offrom 25 to 100% fluid coke, the balance being sand, and said compoundingmaterial comprises under 10 wt. percent water and under 12% of a bindermaterial.

5. The form of claim 3 wherein said compounding material is a binder,and said form is baked.

6. An improved metals molding and casting composition consistingessentially of fluid coke, sand, and a compounding material, saidcompounding material comprising water and a binding agent, and saidcomposition being characterized as follows on a weight percent basis oftotal coke and sand:

25 to 100 weight percent-fluid coke,

sand.

Less than 10 weight percent-water.

Less than 12 weight percent-binding material.

the balance being References Cited in the file of this patent UNITEDSTATES PATENTS 1,871,315 Gann Aug. 9, 1932 1,886,252 Gann et al. Nov. 1,1932' 2,218,781 Baggett Oct. 22, 1940 FOREIGN PATENTS 511,794 CanadaApr. 12, 1955

1. A METAL MOLDING COMPOSITION CONSISTING ESSENTIALLY OF FLUID COKE, ANDA COMPOUNDING MATERIAL, SAID FLUID COKE HAVING BEEN PRODUCED BYCONTACTING A HEAVY PETROLEUM OIL COKING CHARGE STOCK AT A COKINGTEMPERATURE WITH A BODY OF FLUIDIZED COKE PARTICLES IN A REACTION ZONEWHEREIN THE OIL IS CONVERTED TO PRODUCT VAPORS AND CARBONACEOUS SOLIDSARE CONTINUOUSLY DEPOSITED ON THE COKE PARTIDES, REMOVING PRODUCTVAPOURS FROM THE COKING ZONE, HEATING A PORTION OF THE COKE FROM THECOKING ZONE IN A HEATING ZONE TO INCREASE THE TEMPERATURE OF SAIDFLUIDIZED PARTICLES, RETURNING A PORTION OF THE HEATED COKE PARTICLESFROM THE HEATING ZONE TO THE COKING ZONE AND WITHDRAWING COKE PRODUCTPARTICLES.